I picked C as the answer to this question but I am not sure?

Question

The difference between production possibilities frontiers that are vowed out and those that are linear is that:

A)bowed out production possibilities frontiers illustrate tradeoffs, whereas linear production possibilities frontiers do not

B)bowed our production possibilities frontiers show increasing opportunity cost, whereas linear ones show constant opportunity cost

C)bowed out production possibilities frontiers are the result of perfectly shift able resources, whereas linear production possibilities frontiers are not

D)linear production possibilities frontiers illustrate real-world conditions more then bowed our production possibilities frontiers.

Answer 1

I would pick B.